Optoacoustic (OA) imaging is a novel technique which allows optical absorption contrast to be visualized noninvasive using laser induced thermoelastically generated ultrasound. In tumors the highest optical absorption contrast is due to the blood/vascularization. Using optoacoustic biomarkers (such as gold nanoparticle-antibody conjugates) the signal of the vascularization could be enhanced or also other specific regions could be targeted. To assess tumor progression the size of the microvessels and the distance between them can be useful information. We found two different methods to quantify these two parameters using OA imaging. OA texture analysis and the analysis of the contrast-to-noise ratio in the reconstructed OA image and the acoustic frequency spectrum analysis in the raw signal. We present a model to predict the potential of using OA texture analysis combined with acoustic frequency spectrum analysis of the OA signal to assess the progression of tumors. The model is based on the simulation of OA signals using a time domain acoustic propagation method and a Fourier reconstruction algorithm, which has been tested with basic phantom studies. The properties of the receive part, the ultrasound (US) probe, such as the element size, center frequency or bandwidth can freely be adapted. This makes it possible to use this model with any OA system using an US system as the receiver. We show that it is possible to assess the size of optoacoustic absobers, such as the size of the microvasculature in tumors, and partly the distance between them using OA imaging. We also show the influence of a limited bandwidth of the US transducer on the outcome and therefore which transducers should be used for which application. The model has also been tested on different tumors in mice.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1455.